mmm... Jetting again

[HobbyMan]

Ok, new main jets and the works. Air jets swapped. I figured that I could just crank down the pilot jet screws so that I don't have to swap them. I ran it and had to get the #3 float pin to move. (sitting in the kitchen with nothing in it made it stick) After a lot of sucking and blowing it finally came loose. After a vac sync, It runs well in all RPM ranges. Tomorrow I will do some more syncing and some adjusting. The cam chain needs adjustment. Then I will assemble the bike and test it out on the road. I MMO'd the cylinders because it hadn't been done in a while. I should have done that after I got it started the first time because I had to do a lot of cranking, and I didn't want to burn up the starter. I noticed that it sounds really good without the bottom of the air box on. Well, I will see if its got power tomorrow(hopefully) Thanks for all the help.

[HobbyMan]

Ok test run complete. It runs amazing at 3k and above. That means that there is something wrong with the low speed circut. I ran it for about 10-20 min not revving above 3k. the plugs are WHITE. Really white. Does that mean that it is way to lean? Originally the carbs had 210 idle air jets in them. I swaped them out for the 180 in the original carbs. I left the 45 idle jets in there. I will try running it with the srews open more to see if that helps. Any more ideas? It just stutters at low rpms but it does run. Under no load it sounds fine.

[DiverRay]

There is a thread on adjusting the carbs/idle screws. IIRC Ken wrote it, and it's in the adjustment section, from the MAIN XS11.com page. Follow the directions and it should help.
It does sound as if you are NOT getting the correct fuel at low RPM's.
Ray

[pggg]

Hob, if the bike runs at very low revs for twenty minutes and the plugs don't soot up slightly, then the low circuit is LEAN alright, ignore the insulator colour, check the plugs' lower metal ring surface for carbon deposit instead, thing is, float/fuel level makes or breaks carb tuning, if fuel levels aren't PERFECT, fiddling jets and screw adjustments still won't give a satisfactory fix

[HobbyMan]

float levels are right on. When I look on the plugs, I check the bottom electrode. So far they are not as white as before but I have it set 2.5 turns out. I think I am going to get a colortune. I am thinging that will help a lot. I don't know what to do about it right now.

[skids]

There is nothing wrong with 2.5 turns out. If you are that close, I wouldn't bother with a colortune. You will benifit more from plug color if you are that close. Colortune is to get you in the ballpark and might tell you if something else is wrong, unless the colortune itself is malfuncting. On mine I get some arching where the connector hooks to the plug.

Originally posted by HobbyMan
float levels are right on. When I look on the plugs, I check the bottom electrode. So far they are not as white as before but I have it set 2.5 turns out. I think I am going to get a colortune. I am thinging that will help a lot. I don't know what to do about it right now.

[HobbyMan]

Is it ok to run more tha 2.5 turns? Normally my other bikes only run 1.5 out. Actually, I think it needs to back out some more but I thought something would be wrong if it needed more.

[DiverRay]

If you need more than three turns, you might think about going up pne size on the pilot jet.

[pggg]

Crank em' out 6 or 7 turns at least, just to check, there's about 30 turns or something, 1/2 way's 15 turns, brilliant mathematical skills there, should run well then

[skids]

Well, there is math and then there is the real world!

Originally posted by pggg
Crank em' out 6 or 7 turns at least, just to check, there's about 30 turns or something, 1/2 way's 15 turns, brilliant mathematical skills there, should run well then

[pggg]

Yes, admittidly 30 turns is a bit of an exaggeration, just checked on some 78 carbs, there's about 12 - 15 or so revolutions until the screws come out completely, the carbs were pretty well strangled with emission controls at the factory or showrooms, unscrewing those jets a bit more does give a better response down low in most cases

[HobbyMan]

I will crank them out some more, but I want to keep spring pressure on them to keep them from turning on their own

[planedick]

Idle jets

45 idle jets need 210 idle airjets, 42.5 idle jets need 180, that's the only way to get the fuel to air ratio without many turns on the screws which will probably work, but not as well as the right combination of jets. IMHO

[pggg]

45 idle jets with 180 air idle jets and free-flow air filter 4-1 with drilled airbox work real well on my hotted up motor with 78' carbs, with the fuel levels at stock 25-26mm. When cold, starts on one touch with full choke, with a sticky throttle(deliberate) I shut the choke off within seconds and set the motor idling strong and smooth at 1200 revs immediately, no hesitation or fluffiness, and when warmed up, sits on 1000 revs at idle with the throttle shut, always has plenty of drive or torque from idle to 3000, but there's a few differences between stock and 'tricked out' motors

[HobbyMan]

Bieing that it is kinda running lean (I think) wouldn't going back to 210 air jets or going to 42.5 lean it even more. It has 180 air with 45 idles. In theory that should be really rich. I need to just run it some more to find out what it is actually doing. I should be getting a colortune within the next few weeks to help